발열을 동반한 호중구감소증에서 Cefepime 단독투여와 Ceftazidime 및 Tobramycin 병합투여의 효능비교

정현욱,채제욱,강미라,양정채,문치숙,기현균,장현하,오원섭,김기현,백경란,이남용,송재훈 대한감염학회 2004 감염과 화학요법 Vol.36 No.6

목적 : 국내에서 발열을 동반한 호중구감소증이 있는 악성 종양환자에게 경험적 항생제로 베타락탐계 항생제와 아미노배당체의 병합요법의 사용이 일반적이다. Cefepime은 광범위 항균 작용을 가지고 있어, 그람 음성균 뿐만 아니라 그람 양성균에 대해서도 우수한 효과를 나타낸다. 재료 및 방법: 발열을 동반한 호중구감소증이 있는 악성 종양환자를 대상으로 무작위, 공개, 비교 연구를 시행하였다. 대상 환자를 무작위로 cefepime 단독요법군과 ceftazidime 및 tobramycin 병합요법군으로 나누어 투여하고 각각의 임상적 효능과 안전성을 비교하였다. 구강및 인후 점막염이 있는 환자에서 분리된 녹색 연쇄알 구균에 대한 항생제 내성 정도를 조사하였다. 결과 : 대상환자 89명 중 CA 투여군이 48예(53.9%), CT 투여군이 41예(46.1%)이었다. 발열의 유형별로 MDI는 18예(20.2%), CDI는 9예(10.1%), UF는 62예(69.7%)로 두 군 간에 차이가 없었다. CA 투여군과 CT 투여군의 임상적 호전률은 시험약 투여 후 2-4일째 각각 91.7%, 85.4% (P=0.31), 치료 종료 시 각각 91.7%, 100% (P=0.15)로 두 군간에 유의한 차이가 없었다. 치료 종료 시 CA 투여군과 CT 투여군의 세균학적 소실률은 모두 100%로 두 군간의 유의한 차이가 없었다(P=0.78). 점막염이 있는 환자로부터 녹색 연쇄알 구균이 분리된 경우는 25예(28.1%)이었으며, 분리된 녹색 연쇄알 구균은 penicillin, ceftriaxone, cefepime, vancomycin에 모두 감수성을 보였다. 약제 관련 이상 반응의 발생 빈도도 두 군간에 유의한 차이가 없었다. 결론 : 발열을 동반한 호중구감소증이 있는 악성 종양환자의 경험적 항생제로서 cefepime 단독요법은 ceftazidime 및 아미노배당체의 병합요법만큼 효과적이고 안전하였다. Background : Broad-spectrum antibiotic therapy has been recommended as an empirical regimen in cancer patients with febrile neutropenia. Cefepime is a fourth generation cephalosporin with good activity against both gram-positive cocci and gram-negative bacilli. Materials and Methods : To compare the efficacy and safety of cefepime alone with ceftazidime plus tobramycin as empirical regimen for adult cancer patients with febrile neutropenia, a randomized, open label, comparative trial was performed. If the patient showed clinical improvent 72 hours, antibiotic could be changed to oral ciprofloxacin. Clinical and microbiological responses were determined at 72 hours and at the end of therapy. To investigate the antimicrobial resistance of viridans streptococci, swab cultures were obtained from throat in all enrolled patients and antimicrobial susceptibility tests were performed by using microdilution method according to the NCCLS. Results : A total of 89 patients were enrolled. Forty-eight patients received cefepime alone (CA), and 41 patients received ceftazidime plus tobramycin (CT). Demographic and baseline clinical characteristics were similar in both groups (P>0.05). The initial clinical success rate at day 2-4 in group CA (91.7%) was similar with that in CT group (85.4%) (P=0.31). At the end of therapy, the final clinical success rate in CA group (91.7%) was similar to that in CT group (100%) (P=0.15). In 18 patients, with microbiologically defined infections, the eradication rate was 100% in both groups. Adverse events including liver dysfunction (21.3%) and renal dysfunction (2.2%), were similar in both groups (P=0.87). Viridans streptococci were isolated from the throat cultures in 25 cases, and all of these strains were susceptible to penicillin (MIC_(90) 0.12 ㎍/mL), cefepime (1 ㎍/mL), and vancomycin (0.12 ㎍/mL). Conclusion : Efficacy and safety of cefepime monotherapy was comparable to the combination of ceftazidime and tobramycin. It could be used as an alternative empirical regimen for treating cancer patients with febrile neutropenia.

상아질 접착에서 collagenase와 esterase가 미세인장결합강도에 미치는 영향

정영정,현홍근,김영재,김정욱,이상훈,김종철,한세현,장기택 대한소아치과학회 2007 大韓小兒齒科學會誌 Vol.34 No.2

상아질-레진 접착강도에 대한 collagenase와 esterase의 영향을 살펴보기 위해, 소구치의 교합면 상아질에 Single Bond 2와 Clearfil SE Bond로 접착을 시행하고 미세 시편을 제작하여 PBS, collagenase 용액, esterase 용액에 4주간 보관한 후 미세인장결합강도를 측정, 비교하여 다음과 같은 결론을 얻었다. 1. 모든 보관 용액에서 Single Bond 2의 미세인장결합강도는 Clearfil SE Bond보다 유의하게 낮았다(p<0.05). 2. Single Bond 2의 미세인장결합강도는 collagenase군이 PBS군, esterase군보다 낮았다(p>0.05). 3. Clearfil SE Bond의 미세인장결합강도는 esterase군이 PBS군에 비해 낮았으나(p>0.05), collagenase군보다는 높았다(p>0.05). Collagenase군은 PBS군에 비해 유의하게 낮은 미세인장결합강도를 보였다(p<0.05). The purpose of this study was to evaluate the effect of collagenase and esterase on the microtensile bond strength (μTBS) in dentin bonding. After resin composites were bonded to occlusal dentin, μTBS specimens were formed and stored in PBS, collagenase, or esterase solution. After 4-week storage, μTBS was determined and, the results were as follows: 1. μTBS values of Single Bond 2 were lower than those of Clearfil SE Bond for all storage medium (p<0.05). 2. In single Bond 2 group, collagenase solution lowered bond strength more than PBS and esterase solution (p>0.05). 3. In Clearfil SE Bond group, esterase solution lowered bond strength more than PBS(p>0.05). Collagenase solution lowered bond strength more than esterase solution(p>0.05) and PBS(p<0.05).

심실 중격 결손에 의한 감염성 심내막염 환자의 치과치료

양정현,현홍근,김영재,김정욱,장기택,이상훈,한세현,김종철 대한소아치과학회 2007 大韓小兒齒科學會誌 Vol.34 No.3

고빌리루빈혈증을 동반한 자가면역성 간염 1례

서영범,김성욱,장재식,강혁주,이중현,윤병구,김욱년,이광헌,이구,유석동,양창헌,이정호,이영현,이창우,서정일 동국대학교 의학연구소 2000 東國醫學 Vol.7 No.-

자가면역성 간염은 대개 만성 경과를 가지며, 혈중 자가면역항체와 혈청 글로불린치의 상승, 그리고 조직학적으로 괴사 염증성 변화를 특징으로 하는 질환으로 아직 정확한 병인이 밝혀져 있지 않은 상태이다. 발병연령은 대개 젊은 영자(15-25세)에서 호발한다. 이 질환은 급성 간염의 임상경과를 보일 수 있으나, 심한 급성 간염이나 전격성 간염으로도 나타날 수 있는데, 이 경우 아주 나쁜 예후를 보인다고 한다. 치료는 자가면역성 간염 임상 경과의 다양성이나 병인, 병리기전의 불확실성에도 불구하고 대개 steroid 치료에 반응하는 것으로 알려져 있으며 대개 80%의 관해율을 나타내며 궁극적으로 간경변으로의 진행을 막을 수 있는 것으로 보인다. 저자들은 58세 남자에서 발생한 급성의 경과를 가지고 심한 황달을 동반한 자가면역성 간염을 경험하였기에 문헌고찰과 함께 보고하는 바이다. Autoimmune hepatitis (AIH) is a chronic necroinflammatory liver disorder of unknown cause associated with circulating autoantibodies and a high serum globulin level. The age of onset of AIH show a peak between the age of 15 and 25 years. AIH can develop and be manifested as acute hepatitis, but severe form of acute hepatitis or fulminant hepatic failure has a poor prognosis. Although AIH is likely to progress from chronic active hepatitis to cirrhosis, steroid therapy can control the disease activity, prolong survival, improve the quality of life , and defer liver transplantation. In the present report we describe a 58-year-old man who admitted because of progressive jaundice and fatigue. He was diagnosed with AIH from laboratory test result showing positivity for antinuclear antibodies, anti-smooth muscle antibodies, and negativity for hepatitis viral markers and from liver biopsy. Steroid therapy, oral administration of prednisolone, was effective in improving the liver function test. Following liver biopsy 6 months after onset shows markedly improved necroinflammatory activity.

디메틸포름아미드 노출 근로자의 요중 N-메틸포름아미드 분석시 GC-NPD와 GC-FID 방법간 비교

정다운,김현욱 가톨릭대학산업의학센타 산업의학연구소 1999 韓國의 産業醫學 Vol.38 No.1

This purpose of the this study was to compare the results of two analytical techniques, GC-NPD and GC-FID, of quantifying urinary NMF from 70 DMF exposed workers in synthetic resins, leather, and dye manufacturing industries. In addition, the relationship between conecntrations of airborne DMF and urinary NMF was investigated using samples collected from 12 workers. Airborne DMF was sampled using both charcoal and silicagel tubes. All urine specimens were collected both prior-to and at end-of workshifts. The results were as follows: 1. The detection limits of urinary NMF by GC-FID and GC-NPD were 0.043㎎/l and 0.009㎎/l, respectively. The recovery rates were 96.9% for the GC-NPD and 90.2% for the GC-FID methods. 2. Desorption efficiencies of DMF on Charcoal tubes were very poor with 32.96%, while those on silicagel tubes were marginally acceptable with 85.70%. 3. A statistically significant relationship between concentrations of airborne DMF and urinary NMF from 12 workers determined by GC-NPD (r=0.74) and by GC-FID (r=0.67) was observed. 4. Geometric mean concentrations of urinary NMF of the end-of-shift urines from 70 workers were 15.84㎎/g creatinine by GC-NPD and were 9.88㎎/g creatinine by GC-FID, respectivery. For the prior-to-shift samples, they were 6.05 ㎎/g creatinine by GC-NPD and 0.92㎎/g creatinine by GC-FID. These results of this study suggest that for collecting airborne DMF in the workplace, silicagel tubes should be utilized. For quantifying urinary NMF concentrations as a biological marker of DMF exposed workes, urine should be collected at the end-of-shift. Urinary NMF should be analyzed by GC-NPD because of its lower of detection and better precision than that of GC-FID.

온실재배와 노지재배한 금산 깻잎의 품질 특성과 향기성분

현광욱,구교철,장정호,이재곤,김미리,이종수 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2004 한국식품저장유통학회지 Vol.11 No.1

깻잎을 이용한 건강 식품을 개발하고자 먼저 깻잎의 주산지인 금산에서 5월 온실재배한 깻잎과 8월 노지재배한 깻잎들의 품질특성과 향기성분을 조사하였다. 시료깻잎 모두 4.0%의 조단백질과 0.8%의 조지방을 함유하고 있었고, 플라보노이드의 함량은 온실재배 깻잎 25.2%, 노지재배 깻잎 26.5%로 시료깻잎간에 큰 차이는 나타나지 않았으며 조사포닌 함량도 2,7%와 2,8%로 비슷하였다. 시료깻잎의 효소 활성은 오직 알칼리성 단백질 분해효소 활성만이 8월 노지재배 깻잎에서만 물 추출물 7.1 unit, 에탄올 추출불 11.8 unit을 보였고 기타 효소 활성은 없었다. 8월 노지재배 깻잎의 조직감 특성으로 먼저 견고성과 탄력성 등은 잎의 상층부와 중층부 보다 잎받침을 포함하는 하층부에서 높았고 응집성은 하층부가 약간 약하였으며 5월 온실재배 깻잎은 씹힘성이 다서 낮았을 뿐 노지재배 깻잎과 비슷하였다. 5월 온실재배와 8월 노지재배 깻잎에는 1-octen-3-ol, linalool, β-caryorhyllene, α-caryophyllene, α-famesene, perilla ketone, nerolidol, eugenol. α-cadinol 등 14종∼15종의 향기성분을 함유하고 있었고 주요한 향기성분은 perilla ketone 이었다. Quality and flavor compounds of perilla leaves cultivated in greenhouse(May) and field (August) in Geumsan province were investigated and compared. All perilla leaves contained 4.0% crude protein and 0.8% crude lipid. C겨de flavonoid contents of perilla leaves cultivated in greenhouse and field showed 25.2% and 26.5%, respectively and each crude saponin content was cultivated in field. Hardness and chewness of bottom parts of field-perilla leaves were higher than those of top and middle part, whereas the cohesiveness of top parts and middle parts of perilla leaves were higher than that of bottom part. Furthermore, texture properties of greenhouse-perilla leaves were similar with those of field-perilla leaves except chewness. Nine kind of flavor compounds such as 1-octen-3-ol, linalool, β-caryophyllene, α-caryophylene, α-franesene, perilla ketone, nerolidol, eugennl, α-cadinol were identified in greenhouse-perilla and field-perilla leaves, showing that main flavor compound was perilla ketone.

尤怡의 醫學思想에 關한 硏究

鄭城采,金基郁,朴炫局 동국대학교 한의학연구소 1997 東國韓醫學硏究所論文集 Vol.6 No.1

동양의학에서 『傷寒論』의 발전은 대체로 三段階의 과정을 거쳤으나 "三綱鼎立"설이 대세를 이루고 있었다. 이러한 관점에 대항하여 辨證論治規律을 연구한 學派가 나타나게 되었는데 尤怡가 그 중 한사람이다. 尤怡의 生涯, 著書, 學術思想 및 후세에 미친 영향 등을 조사하고 특히 『傷寒論』을 按法類??하여 六經에 따른 正治法ㆍ權變法ㆍ斡旋法ㆍ救逆法ㆍ類病法ㆍ明辨法ㆍ雜治法 등의 治法에 대하여 연구하여 보고하는 바이다. The present writer studied the medical thought of 'You-Yi'(尤治)', the medical expert of the early 'Qing(辯)' Dynasty, which can be summarized as following. 1. 'You-Yi' writed many essays nnd treaties about 'Shang-Han-Lun(傷寒論)' and 'Jin-Gui-Yao-Lue(金?要略)', both of which are the writings of 'Zhang-Zhong-Jing(張仲景)', the medical saint of 'Han(漢)' Dynasty, and those writings include 'Shang-Han-Guan-Zhu-Ji(傷寒貫球集)', 'Jin-Gui-Yoo-Lue-Xin-Dian(金?要略心典)', 'Yi-Xue-Dou-Shu-Ji(醫學讀書記)', 'Jin-Gui-Yi(金?翼)', and ‘Jing-Xiang-Lor-Yi-An(靜番樓醫案)'. 2. A theory of 'Tai-Yang(太陽)' syndrome, including 'San-Gang-Ding-Li(三網鼎立)', was proposed by 'Fang-Han-Lun(方有執)' and 'Yu-Chang(喩昌)' and it came to be one of the leading theory of the'Shang-Han-Lun'. 'You-Yi' rejected their opinions in which they insisted that the'Feng(風)' hurts the 'Wei(衛)' and the 'Han(寒)' hurts 소e 'Ying(營)', and he advocated his particular idea that the 'Xie Qi(邪氣)' can directly hit skin, flesh, 'Ying-Wei(營衛)', the Five Organs and the Six Viscera(五臟六腑), regardless of 'Zhong-Feng(中風)' or 'Shang-Han(傷寒)', and he insisted that there is need to be anxious about whether the 'Ying-Wei' is strong or weak. 3. In 'Shang-Han-Guan-Zhu-Ji', 'You-Yi' invented the eight classifications in treating the'SHang-Han' and he did not follow the old theories hitherto. He divided the book into six parts via the clinical experiences, and the Classification and Logics in Treatment(辯證論治), and he put several titles on'Jin-Gui-Yao-Lue'. And he newly edited the original text of'Shang-Han-Lun' and arrnnged 'Zhong-Jing(仲景)'s Six Meridian(六經) categories. Each syndrome in'Tai-Yang', 'Yang-Ming(陽明)', 'Shao-Yang(少陽)', 'Tai-Yin(太陰)', ‘(Shao-Yin(小陰)’and 'Jue-Yin(?陰) has its own categories in treatment. 4. In explaining the Six Meridians(六經) and Organs and Viscera(臟腑), ‘You-Yi' legislated the syndrome in 'Three Yang(三陽)’ into Meridians(經) and Organs(臟). He also concluded that 'Shang-Han-Lun' not only discusscd 'Wai-Gan(外感)' but also included the Internal Hurt(內傷) and Miscel1aneous Diseases(雜病). 5. In his academic research,'You-Yi' followed 'Zhong-jing' in classifications and prescriptions and succeeded the theory of "Ma-Chu(馬?)' and 'Li-Zhong-Zi(李中粹)', but was not tied to any stereotyped former practices. He put emphasis on the Spleen(脾) and the Kidney(腎) as he harmonized the Middle Energizer(中焦焦) with the taste of 'Gan(甘)' and 'Wen(溫)' and enjoyed strengthening 'Yang' by benefitting the 'Qi(氣)' 6. He discusscd in detail the causes, mechanism and symptoms on 'Tan-Yin(疫飮)' and proposed the seven categorizes in treatment. 7. He sorted the causes of 'Zhong-Feng' into two kinds of the 'Feng' via 'Wai-Gan' and Internal Hurt, and recognized these two 'Feng's correlate as mutual sources of diseases. He insisted that the origin of the 'Fing' exists in the 'Liver(肝)’. He also established the eight categories in treating the'Feng'. 8, 'You-Yi' belongs to the Classification and Logical Treatment School. And he, considering he respected and followed "Zhong-Jing' and 'Li-Zhong-Zi', belongs to the successor to the 'Wen-Bu(溫補)' School. 9. His writings, especially the 'Shang-Han-Guan-Zhu-Ji' and the 'Jin-Gui-Yao-Xin-Dian', are excellent commentary works on the originals, so they served as significant guide books for many junior scholars. For penetrating the 'Shang-Han-Lun" with his unique way of classification of treatment, he has been highly appreciated by later generations including scholars like 'Tang-Li-San(唐立三)' in the 'Qing' Dynasty, and so many more ones thenceforth. In conclusion, on the base of this study, it is hopefully proposed that the still more profound research on the medical thought of 'You-Yi', as one of the most distinguished scholars, an expert clinician and an earnest writer as we11.

법랑질 표면처리방법에 따른 치면열구전색재의 미세누출에 관한 비교연구

현홍근,김정욱,이상훈 대한소아치과학회 2001 大韓小兒齒科學會誌 Vol.28 No.3

최근 air-abrasion기술이 새로운 법랑질 표면처리법으로 소개되고 있는데, 이것이 산부식 처리한 것보다 치면열구전색 전처리에 있어 더 나은 결과를 보이는지 연구할 목적으로.저자들은 표면처리법 및 재료에 따른 미세누출도의 차이를 비교해 보고자 하였다. 9개의 군으로 나눈 시편치아에 산부식(1, 4, 7군). air-abrasion(2. 5, 8군). ail·-abrasion후 산부식(3. 6. 9군) 처리한 후, 3종의 치면열구전색재(1∼3군 : Teethmate-F.4∼6군 Ultraseal XT plus, 7∼9군 : DenSeal)로 전색, 중합하여 색소침투도를 관찰하였으며, 각 시편의 전색재를 분리, 주사전자현미경으로 관찰하여 다음과 같은 결과를 얻었다. 1 표면처리법에 따른 미세누출도는 air-abrasion군, 산부식군 air-abrasion 후 산부식군 순으로 작아졌다(p<0.05) . 단. 7군과 9군간의 유의차는 없었다. 2.미세누출도는 산부식군에서 7군, 4군, 1군, air-abl·asion군에서 8군, 5군, 2군, air-abrasion후 산부식군에서 9군, 3군. 6군 순으로 작아졌으나. 각각 4군과 7군 2군과 5군 3군과 6군간의 유의차는 없었다. 3. SEM상에서, 산부식군은 비교적 긴 레진돌기가 규칙적으로, air-abrasion군은 �裏�레진돌기가 불규칙적으로, air-abrasion후 산부식군에서는 이들이 혼재되어 있는 모습으로 관찰되었다. Recently, the reintroduction of air-abrasion technology in dentistry has added a new potential method of pre-treating teeth prior to placing sealants. The purpose of this in vitro study was to investigate microleakages of several pit and fissure sealants following various surface pre-treatment methods to the enamel , because there was a question concerning the validity of claim that this method was better than the conventional acid etching. Permanent molars were divided randomly into nine groups and treated accordingly: acid etching(group 1, 4, 7), airabrasion(group 2, 5. 8), acid etching after airabrasion(group 3, 6, 9). Then the authors placed and cured the three kinds of sealants(group 1∼3 : Teethmate-F, group 4∼6: Ultraseal XT plus, group 7~9: Denseal) according to the manufacturer's order. They were observed to determine the degree of microleakage . And these specimens were separated from the corresponding enamels and examined by Scanning Electron Microscope. The following results were obtained : 1. In comparing microleakage among tooth surface treatment methods. air-abrasion group (group 2, 5, 8) showed the greatest microleakage. while combination(air-abrasion + acid etching) group showed the least (p<0.05) . However, no significant differences were found between group 7 and 9. 2. The mean microleakages were ranked as follows(p<0.05) : In acid etching groups. group 7> group 4> group 1. In air-abrasive groups. group 8 > group 5 > group 2. In combination groups, group 9 > group 3 > group 6. However. no significant differences were found between group 4 and 7. between group 2 and 5, and be-tween group 3 and 6. 3. SEM showed that comparably longer resin tags were distributed regularly in acid etching groups and that shorter ones irregularly in airabrasion groups. It also showed that these two kinds of tags were distributed simultaneously in combination groups.

Collagenase와 esterase가 상아질 접착강도와 nanoleakage에 미치는 영향

정영정,한세현,김종철,이상훈,김정욱,김영재,장기택 大韓小兒齒科學會 2008 大韓小兒齒科學會誌 Vol.35 No.3

본 연구는 상아질 접착계면에서 collagenase와 esterase가 접착강도와 극미세누출에 미치는 영향을 살펴보기 위해 시행하였다. 발치된 치아의 교합면 상아질에 Single Bond 2(SB)와 Clearfil SE bond(SE)를 사용하여 상아질-레진 접착시편을 제작하고,시편을 인산완충용액(PBS)에 24시간(I),또는 PBS(II),collagenase 용액(III),esterase 용액(IV)에 4주간 보관 한 후 질산은 용액으로 염색하였다. 시편의 미세인장접착강도(μTBS)와 질산은 침투 면적을 측정하여 다음과 같은 결과를 얻었다. 1. SB군의 접착강도가 II∼IV군에서 SE군에 비해 낮은 값을 나타내었다(p<O.05). SB군은 II∼IV군의 접착강도가 I군에 비해 낮은 값을 보였으나(p<O.05),SE군의 접착강도는 I∼IV군간에 차이를 보이지 않았다(p>O.05). 2. SB군의 질산은 침투 면적이 SE군에 비해 높았으며(p<O.05),SB군과 SE군에서 질산은 침투 면적은 I ∼ IV군간에 차이를 보이지 않았다(p>O.05). 3. 접착강도와 질산은 침투 면적은 SE군의 I, II,III군에서 음의 상관관계를 보였다(p<O.05). The purpose of this study was to evaluate the effects of collagenase and esterase on dentin bond strength and nanoleakage. Resin composites were bonded to occlusal dentin of premolars with Single Bond 2(SB) and Clearfil SE Bond(SE). After the microtensile specimens were prepared and stored in PBS for 24 hours(I) or, PBS(II), collagenase(III), esterase(IV) solution for 4 weeks, the specimens were stained with silver nitrate solution. Microtensile bond strength(μTBS) and silver penetration area were measured and, the results were as follows: 1. For group II, III, and IV, the bond strengths of SB were lower than those of SB(p<0.05). The bond strengths of SB II, III, and IV were lower than that of SB I(p<0.05). There was no difference among the bond strengths of SE I ∼ IV groups(p>0.05). 2. Silver penetration areas of SB were higher than those of SE for all storage groups(p<0.05). In SB and SE groups, there was no significant difference of silver penetration area among I ∼ IV groups(p>0.05). 3. SE I, II, and III showed inverse relationship between the bond strengths and the silver penetration areas(p<0.05).

EDM 가공 공정에서 세장비 극대화를 위한 미세구멍의 최적가공 조건 결정

정종혁,이현욱,권원태 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

Demand of micro holes has been increased fast, especially in the area of inkjet nozzle, micro turbine and optical parts. However, the micro hole with 40㎛ exit diameter and aspect ratio of 10 has yet to be reported. In this study, an endeavor was made to manufacture the micro hole under over 40㎛ exit diameter at stainless steel plate with 40㎛ thickness. To accomplish the goal, the relationship between machining parameters and machined result was identified. It was found that the entrance clearance was proportional to the discharge power, when discharge energy was kept constant and resistance had to be as high as possible at the given condition to minimize the machining time. 40㎛ average diameter of the micro hole with over 10 aspect ratio was achieved under the condition of 60V, 680pF, 500Ω, 1.5㎛ and 1500rpm.